July 20, 2022 Summer Favorites

All images were acquired with Celestron 8 SCT on AVX mount with ZWO ASI294MC Pro using Starizona Night Owl operating at F/4 and light pollution filter.  Subs for the comet, Sh2-142 and Sh2-155 were 30s typical for the Harvard, MA area. I'll revisit the Sharpless targets with 60s exposures in the future to try to bring out more nebulosity. Exposures respectively for M27(my better half's favorite)  and M13 were 8s and 15s. Update: M13 reprocessed for better contrast. 

M13

Comet C2017K2 PANSTARRS

Sharpless 155

Sharpless 142

M27

Globular Clusters

This is the time of the year to image globular clusters, some of my favorite targets. The bulk of them tend to be low in the southern sky which is a challenge considering seeing and refraction. M13 was included in the previous post. Several others acquired on the same night appear below. M55 was acquired on a later night. Images were averaged from 30x30s subframes acquired at 120 unity gain. Configuration was Celestron 8 , Starizona NightOwl 0.4x focal reducer, ZWO ASI294MC Pro CMOS camera. Update: Images reprocessed with GraXpert stretching and residual gradient removal.

Messier 3

Messier 4

Messier 5

Messier 10

Messier 12

Messier 13

Messier 55

Seasonal Favorites

It's that time of the year, mid summer, to revisit old favorites. I never tire trying to better myself imaging these or other targets. All my recent imaging has been done from increasingly light polluted Harvard MA. Poorly targeted and excessive LED lighting is really trying to kill off night. Nonetheless the Milky Way can still be glimpsed overhead from Harvard. Typically 30 to 60 30 second exposures are acquired at F/4 using the Starizona Night Owl focal reducer corrector, light pollution filter and ZWO ASI294MC Pro using 120 unity gain. Subframes are stacked and averaged with Autostakkert! 3.  Images histograms stretched and images processed in PaintShop Pro 2021. Additional processing done in using Microsoft Photos bundled with Windows 10. 

IC5146 - Cocoon Nebula

Messier 8 - Lagoon Nebula

Messier 16 - Eagle Nebula

Messier 17  - Swan or Omega Nebula

Messier 20 - Triffid Nebula

NGC7023 - Iris Nebula

Messier 13

NGC7380

NGC6992 Eastern Veil Nebula

Recent Activity

I recently acquired a Celestron Motorfocus. What a great accessory. Aside from allowing more precise focusing there is no need to touch the scope (causing shake) or reposition one's self to access a focus knob. One can also enter previously determined number to get close to the focus for a particular optical configuration.  Cool. 

For the first time I visited one of my choice darkish sites it Maryland i.e. McCoy's Landing. It's not as dark as I had hoped thanks to increasing excessive LED street and security in nearby cities but it's better than trying to image from champion light polluter Frederick Maryland. The main target for the night was NGC2359 (Thor's Helmet ). The result below is a start that I hope to improve on when Canis Major returns in late 2022. Also, imaged that night were M48, M67, M81 and Sharpless 274.

NGC2359 (Thor's Helmet)

Messier 48

Messier 67

Messier 81 (Bode's Galaxy)

Sharpless 274

First Images of 2022

Based on Clear Sky Charts forecast the night (1/3/2022) promised to be clear, cold and with poor seeing but I decided to go after a few targets including three comets. Of the six scheduled targets only four produced acceptable images. It appears too much Frederick, MD light pollution as well as nearby illumination was leaking into the scope despite the SCT dew shield. All images were 64x30s subframes except for M33 which was 124x30s. Equipment used: Celestron 8 on AVX mount, Starizona Night Owl 0.4X focal reducer/corrector and ASI294MC Pro. Images were stack averaged in Autostakkert! and then stretched and processed with Paintshop Pro. 

Messier 76 (The Little Dumbell Nebula)

Comet 67P/Churyumov-Gerasimenko

Messier 33 - Triangulum Galaxy

Comet 2019L3 Atlas

Some Early December Images

These images were acquired in the increasingly sprawling and light polluted city of Frederick, MD. The Whittier neighborhood borders a red and white zone which called for 15 to 20s subframes. Each target was imaged for 180 subframes for cumulative exposure times between 45 and 60min. Equipment: Celestron 8/AVX Mount, Starizona Night Owl with Light Pollution Filter, ZWO ASI294MC Pro. 

M31 Andromeda Galaxy

M42 Orion Nebula

NGC2024 (Flame Nebula), NGC2024, B33(Horsehead Nebula)

NGC7789(Caroline's Rose open cluster)

NGC281(Pacman Nebula)

I recently watched Robin Glover's excellent talk on deep sky imaging with one shot color cameras. I also read his SharpCap forum write up on setting the exposure time for a site's sky brightness. Robin also gets into the mathematical justification in the write-up which I like. It seems that for my typical F/4 configuration with the Starizona Night Owl focal reducer, exceeding 30sec sub frame exposures offers no signal to noise benefit. This is a real eye opener. Instead, best practice is to collect as many sub frames to achieve a certain total exposure time. For example 120x30sec exposures for an hour. These concepts were played with the six images below from the most recent two imaging sessions. 

NGC 281 (Pacman Nebula)

NGC 6992 (Eastern Veil Nebula)

NGC 7635 (Bubble Nebula)

Messier 13

NGC 7023 (Iris Nebula)

NGC 7380 (Wizard Nebula)